1. Field of the Invention
The present invention relates to a liquid discharge head that discharges a desired liquid by the bubbles created by the application of thermal energy acting upon the liquid, and also, relates to the head cartridge and the liquid discharge apparatus using such liquid discharge head. More particularly, the invention relates to a liquid discharge head provided with the movable members which are displaceable by the utilization of the creation of bubbles, as well as to a head cartridge and a liquid discharge apparatus using such liquid discharge head.
Also, the present invention is applicable to a printer capable of recording on a recording medium, such as paper, thread, textile, cloth, leather, metal, plastics, glass, wood, and ceramics, among some others. The invention is also applicable to a copying machine, a facsimile equipment having communication systems, and an apparatus, such as a wordprocessor, which is provided with a printer. The invention is also applicable to a recording system for industrial use arranged complexly in combination with various processing apparatuses.
Here, in the specification of the present invention, the term xe2x80x9crecordxe2x80x9d means not only the provision of characters, graphics, and other meaningful images, but also, it means the provision of patterns or other images, which do not present any particular meaning, for a recording medium.
2. Related Background Art
There has been known the ink jet recording method, that is, the so-called bubble jet recording method in which energy, such as heat, is given to ink to cause the change of states thereof which is accompanied by the abrupt voluminal changes (creation of bubbles), and ink is discharged from the discharge ports by the acting force based on this change of states, and then, the discharged ink is allowed to adhere to a recording medium for the formation of images. The recording apparatus using this bubble jet recording method is generally provided with the discharge ports for discharging ink; the ink flow paths communicated with the discharge ports; and the electrothermal transducing devices each arranged in each of the ink flow paths, serving as means for generating energy used for discharging ink as disclosed in the specifications of U.S. Pat. No. 4,723,129, and others.
In accordance with a recording method of the kind, it is possible to record high quality images at higher speeds in a lesser amount of noises. At the same time, with the head whereby to execute this recording method, it becomes possible to arrange the discharge ports for discharging ink in higher density, among many other advantages, hence obtaining recorded images in higher resolution with a smaller apparatus, as well as obtaining images in colors with ease. In recent years, therefore, the bubble jet recording method is widely utilized for many kinds of office equipment, such as printer, copying machine, facsimile equipment, and further, utilized for the textile printing system and others for the industrial use.
Now, along with the wider utilization of the bubble jet technologies and techniques for the products currently in use in many fields, there have been various demands increasingly more in recent years as given below.
In order to obtain images in higher quality, the driving condition is proposed anew so that the liquid discharge method or the like should be arranged to perform good ink discharges on the basis of the stabilized creation of bubbles that enables ink to be discharge at higher speeds. Also, from the viewpoint of the higher recording, there has been proposed the improved configuration of flow paths so as to obtain the liquid discharge head which is capable of performing in the liquid flow paths the higher refilling for the liquid that has been discharged.
Besides a head of the kind, an invention is disclosed in the specification of Japanese Patent Application Laid-Open No. 6-31918 (particularly, with reference to FIG. 3 in the Application) in which attention is given to the back waves (the pressure directed in the direction opposite to the one toward the discharge ports) which are generated along with the creation of bubbles, and then, the structure is arranged to prevent such back waves because the back waves result in the energy loss in performing discharges. In accordance with the invention disclosed in the specification thereof, the triangle portion of a triangular plate member is arranged to face each heater that creates bubbles. The invention can suppress the back waves temporarily and slightly by means of such plate member thus arranged. However, there is no reference at all as to the correlations between the development of bubbles and the triangular portion nor any idea is disclosed as to dealing with such correlations. Therefore, this invention still present the problems as given below.
In other words, the invention thus disclosed is designed to locate the heaters on the bottom of a recessed portion, thus making it difficult to provide the condition where the heaters can be communicated with the discharge ports on the straight line. As a result, each liquid droplet is not stabilized in keeping its shape uniformly. At the same time, since the development of each bubble is allowed to take place beginning with the circumference of each apex of the triangular portions, the bubble is developed from one side of the triangular plate member to the opposite side entirely. Consequently, the development of each bubble is completed in the liquid as has been usually effectuated as if there were no presence of the triangular plate members. Here, as to the bubble development, therefore, the presence of the plate members has no bearing at all. On the contrary, the entire body of each plate member is embraced by each bubble, and in the stage where the bubble is contracted, this condition may bring about the disturbance in the refilling flow to each of the heaters located in the recessed portion. As a result, fine bubbles are accumulated in the recessed portion, which may disturb the principle itself with which to perform discharges on the basis of the development of bubbles.
Meanwhile, in accordance with the laid-open EP publication 436047A1, an invention has been proposed to alternately open and close a first shut off valve arranged between the area in the vicinity of discharge ports and the bubble generating portion, and a second valve which is arranged between the bubble generating portion and the ink supply portion in order to shut them off completely (as shown in FIGS. 4 to 9 of the EP436047A1). However, this invention inevitably partitions each of the three chambers into two, respectively. As a result, the ink that follows the liquid droplet presents a great trailing at the time of discharge, which creates a considerable amount of satellite dots as compared with the usual discharge method where the development, contraction, and extinction are performed for each of bubbles (presumably, there is no way to effectively utilize the resultant retraction of meniscus in the process of the bubble disappearing). Also, at the time of refilling, liquid should be supplied to the bubble generating portion following the bubble disappearing of each bubble. However, since it is impossible to supply liquid to the vicinity of each discharge port until the next bubbling takes place, not only the size of each discharge liquid droplet varies greatly, but also, the frequency of discharge responses becomes extremely smaller. This proposed invention is, therefore, far from being practical.
On the other hand, the applicant hereof has proposed a number of inventions that may contribute to the performance of effective discharges of liquid droplets, which use the movable member (the plate member or the like that has its free end on the discharge port side of its fulcrum) unlike the conventional art. Of the inventions thus proposed, the one disclosed in the specification of Japanese Patent Application Laid-Open No. 9-48127 is such as to regulate the upper limit of the displacement of the movable member in order to prevent even a slight disturbance of the behavior of the movable member as described above. Also, in the specification of Japanese Patent Application Laid-Open No. 9-323420, there is the disclosure of an invention that the position of the common liquid chamber on the upstream of the aforesaid movable member is arranged to be shiftable to the downstream side, that is the free end side of the movable member, by the utilization of the advantage presented by the movable member so as to enhance the refilling capability. However, for these inventions, no attention has been given to each individual element of bubbling as a whole which is concerned with the formation of the liquid droplet, or to the correlations between each of them, because in the premises set forth for the designing the invention, the mode has been adopted so that the bubble is released to the discharge port side at once from the state where the development of the bubble is temporarily embraced by the movable member.
Then, in the next stage to follow in this respect, the applicant hereof has disclosed in Japanese Patent Application Laid-Open No. 10-24588 the invention that a part of the bubble generation area is released from the movable member as a new devise (acoustic waves) with the attention given to the development of bubble by the application of the propagation of pressure waves, which constitutes the element related to the liquid discharges. However, for this invention, too, the attention is given only to the development of each bubble at the time of liquid discharges. As a result, each individual element related to the formation of the liquid droplet itself, with which bubbling is concerned as a whole, nor the correlations between each of them is taken into consideration when the invention is designed.
Although it has been known that the front portion (edge shooter type) of the bubble created by means of the film boiling exerts a great influence on the discharges, there is no invention in which attention has ever been given to this particular portion so as to make it effectively contributive to the formation of each discharge liquid droplet. The inventors hereof have ardently studied this portion in order to elucidate it technically when designing the invention taken out for patent herein.
From the viewpoint of the formation of discharge liquid droplets, the precise analyses are made as to the processes from the creation of each bubble to the bubble disappearing thereof. Then, a number of inventions are designed as a result of such precise analyses. The present invention is one of them thus devised for the reduction of the satellites which are characteristic of ink jetting, and which tend to lower the quality of prints, and also, cause the apparatus itself and the recording medium to be stained. As compared with the conventional art, the present invention makes it possible to attain an extremely high technical standard with respect to the stabilization of the image quality in the execution of the continuous discharge operation.
The main objectives of the present invention are as follows:
A first object of the invention is to provide an extremely novel liquid discharge principle under which the created bubbles and the liquid on the discharge port side thereof, as well as the liquid on the supply side, are suppressed by the presence of the movable members and the structural arrangement of the entire liquid flow paths.
A second object of the invention is to provide a liquid discharge method and a liquid discharge head with which the reduction of satellites is implemented by controlling the formation process of each discharge liquid droplet, and substantially the satellites in the discharge operation is eliminated.
A third object is to lighten the system load of the structure needed for a recording apparatus to make it possible to remove the drawbacks resulting from the presence of satellites and the fluctuation of meniscus.
In order to achieve these objectives, the liquid discharge head of the invention comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port, having a bubble generation area for enabling liquid to create bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; and a regulating member to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid dischrge head, the liquid flow path holds bubble at the time of bubbling, being provided with a gap arranged on side of the movable member to allow the liquid on the upstream of the movable member to flow into the bubble generation area at the time of bubble disappearing.
Also, the liquid discharge head of the invention comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port, having a bubble generation area for enabling liquid to create bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; and a regulating member to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid discharge head, the regulating member is arranged to face the bubble generating area of the liquid flow path, and the liquid flow path having the bubble generation area becomes an essentially closed space with the exception of the discharge port when the vicinity of the free end of the displaced movable member is substantially in contact with each of the regulating member, and the movable member is displaced to be resiliently extruded to the upstream side before the bubble presents the maximum volume, and then, the extruded portion thereof is displaced to the downstream side by the resiliency thereof in the stage of the bubble contraction.
Also, the liquid discharge head of the invention comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port, having a bubble generation area for enabling liquid to create bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; and a regulating member to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid discharge head, the liquid flow path having the bubble generation area becomes an essentially closed space with the exception of the discharge port when the displaced movable member is substantially in contact with the regulating member, and, the bubble does not block the liquid flow in the space at the time of maximum bubbling.
Also, the liquid discharge head of the invention comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port, having a bubble generation area for enabling liquid to create bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; and a regulating member to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid discharge head, the liquid flow path having the bubble generation area becomes an essentially closed space with the exception of the discharge port when the displaced movable member is substantially in contact with the regulating member, and there exists the liquid facing the movable member when the bubble is developed to the maximum and being connected continuously with the liquid on the downstream side of the bubble generation area in the space.
Also, the liquid discharge head of the invention comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port, having a bubble generation area for enabling liquid to create bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; and a regulating member to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid discharge head, the liquid flow path having the bubble generation area becomes an essentially closed space with the exception of the discharge port when the displaced movable member is substantially in contact with the regulating member, and the bubble does not cover the substantially contacted portion of the movable member at the time of maximum bubbling.
Also, the liquid discharge head of the invention comprises a heating member for heating liquid in a liquid flow path to create bubble in the liquid; a discharge port communicated with the downstream side of the liquid flow path for discharging the liquid by the pressure along with the development of the bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; a regulating member to regulate the displacement of the movable member within a desired range, and the heating member and the discharge port being in the linearly communicated state, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid dischrge head, the regulating member is arranged to face the bubble generation area, and the liquid flow path having the bubble generation area becomes an essentially closed space with the exception of the discharge port when the displaced movable member is substantially in contact with the regulating member, and the movable member covers a part of the heating member at the time of bubble extinction so as to cause the liquid on the area covered by the movable member to flow out from the side of the movable member.
Also, the liquid discharge head of the invention comprises a heating member for heating liquid in liquid flow path to create bubble in the liquid; a discharge port communicated with the downstream side of the liquid flow path for discharging the liquid by the pressure along with the development of the bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; a regulating member to regulate the displacement of the movable member within a desired range, and the heating member and the discharge port being in the linearly communicated state, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid dischrge head, the regulating member is arranged to face the bubble generation area, and the liquid flow path having the bubble generation area becomes an essentially closed space with the exception of the discharge port when the displaced movable member is substantially in contact with the regulating member, and the movable member covers the extinct point of the bubble at the time of bubble extinction.
Also, the liquid discharge head of the invention comprises a discharge port for discharging liquid; a liquid flow path communicated with the discharge port, having a plurality of bubble generation areas for enabling liquid to create bubble; and movable member arranged in the liquid flow path to face the bubble generation area, having a free end on the downstream side with respect to the liquid flow in the direction toward the discharge port, the movable member being arranged only in the bubble generation area on the upstream side in the liquid flow direction toward the discharge port among the plurality of bubble generation areas.
Also, in order to achieve the objects described above, the liquid discharge apparatus of the invention comprises a liquid discharge head described in either one of the preceding paragraphs, and means for carrying a recording medium to carry the recording medium that receives liquid discharged from the liquid discharge head.
Further, for the achievement of the objects described above, the liquid discharge method of the invention, which uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port, having a bubble generation area for enabling liquid to create bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; and a regulating member to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the steps of holding the bubble by the movable member when the bubble is developed, and enabling the liquid on the upstream of the movable member to flow into the bubble generation area through the gap provided for the side of the movable member at the time of bubble disappearing.
Also, the liquid discharge method of the invention, which uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port, having a bubble generation area for enabling liquid to create bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; and a regulating member to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the steps of contacting the movable member essentially with the regulating member before the maximum bubbling of the bubble, displacing the movable member to be resiliently extruded to the upstream side to make the liquid flow path having the bubble generation area an essentially closed space with the exception of the discharge port, and displacing the extruded portion of the movable member to the downstream side by the resiliency thereof in the contracting stage of the bubble.
Also, the liquid discharge method of the invention, which uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port, having a bubble generation area for enabling liquid to create bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; and a regulating member to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the steps of contacting the movable member essentially with the regulating member before the maximum bubbling of the bubble, allowing no bubble to block the liquid flow in the space at the time of maximum bubbling.
Also, the liquid discharge method of the invention, which uses the liquid discharge head provided with a heating member for heating liquid in a liquid flow path to create bubble in the liquid; a discharge port communicated with the downstream side of the liquid flow path for discharging the liquid by the pressure along with the development of the bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; a regulating member to regulate the displacement of the movable member within a desired range, and the heating member and the discharge port being in the linearly communicated state, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the steps of contacting the movable member essentially with the regulating member before the maximum bubbling of the bubble to make the liquid flow path having the bubble generation area in it an essentially closed space with the exception of the discharge port; enabling the movable member to cover a part of the heating member before the bubble disappearing of the bubble; and allowing the liquid on the area covered by the movable member to flow out from the sides of the movable member.
Also, the liquid discharge method of the invention, which uses the liquid discharge head provided with a heating member for heating liquid in a liquid flow path to create bubble in the liquid; a discharge port communicated with the downstream side of the liquid flow path for discharging the liquid by the pressure along with the development of the bubble; a movable member arranged in the bubble generation area to be displaced along with the development of the bubble; a regulating member to regulate the displacement of the movable member within a desired range, and the heating member and the discharge port being in the linearly communicated state, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the steps of contacting the movable member essentially with the regulating member before the maximum bubbling of the bubble to make the liquid flow path having the bubble generation area in it an essentially closed space, and enabling the movable member to cover the bubble disappearing point of the bubble at the time of the bubble disappearing of the bubble.
In accordance with the valve mechanism of the movable members of the present invention, it becomes possible to suppress the deflection of each movable member by allowing the bubble to be extruded around the backface of the movable member, hence stabilizing the discharge characteristics. Further, at the time of bubble disappearing, a xe2x80x9cwellxe2x80x9d type condition is formed in each of the bubble generation areas to eliminate the residual bubble accumulation and the heat accumulation in the vicinity of each heating member even for the structure having no liquid circulation systems in it. Also, it is possible to prevent or suppress the liquid shift in the upstream diection which follows the back waves, that is, the pressure waves in the upstream direction. The resistance that liquid receives from each liquid flow path is made smaller to enhance the refilling capability. Also, the inertia exerted by the back waves that may act in the direction opposite to the liquid supply direction is suppressed, and the meniscus is drawn rapidly into each dischrge port. However, such rapid draw of meniscus is controlled to cease before the amount of meniscus retraction becomes greater. In this manner, the creation of satellite dots is prevented to improve the refilling frequency, and the printing speed, among others. Moreover, the vibrations of the meniscus is suppressed to stabilize discharges for the enhancement of the quality of prints. Also, when the valve mechanism is allowed to act by the creation of bubbles, the resistance that each of the movable members receives from the liquid flow path is made smaller up to a specific dispalcement postion of the movable member so that the movable member can reach an appropriate displacement position quickly. In this way, the discharge efficiency is improved.
Also, in accordance with the present invention, before the major refilling is initiated, the inertia in the stationary condition as described above is relaxed to initiate its shift in the refilling direction. As a result, the refilling can be performed stably and quickly, which contributes to the formation of liquid droplets sufficiently. Also, the meniscus is drawn into each discharge port rapidly, the liquid shift in the upstream direction, which follows the back wave, that is, the pressure waves in the upstream direction, is suppressed to prevent the creation of satellite dots for the stabilization of discharge amount and the enhancement of the quality of prtints.
Also, in accordance with the present invention, it is possible to suppress the liquid shift in the upstream direction following the back waves, that is, the pressure waves in the upstream direction, and at the same time, secure the liquid flow, that is, fluid, in good condition by allowing the bubble to release the closed space, particularly the portion where each movable member is in contact, from the state of being blocked when the volume of the bubble is reduced to initiate the refilling subsequent to the formation of the essentially closed space based upon the development of the bubble. Hence, it becomes possible to enable each movable member to be restored at a high speed, and stabilize the discharge amount for the enhancement of the quality of prints.
Also, in accordance with the present invention, it is arranged to secure the fluid current with respect to the narrow space (approxiamtely 10 micron) between the fulcrum side of each movable member and the bubble generation area by the utilization of cavitation, thus making the entire refreshing possible.
Also, in accordance with the present invention, the formation of liquid droplets can be performed stably without creating the microdots. As a result, the overall qulaity of prints is improved.
Particularly with the structure of the present invention in which the trailing portion connected with the discahrged droplet to form the liquid column is cut off from the meniscus quickly for the high-speed settlement of the meniscus vibrations, it becmes possible to perform the higher-speed recording in higher quality by the higher liquid discharges by attaining good responses at the time of continuous discharges, as well as the stabilized formation of liquid dorplets.
Further, in accordance with the liquid discharge head of the present invention, each of the liquid flow paths is essentially divided with respect to the liquid flow in the direction toward the discharge port when the movable member is displaced to be in contact with the regualating member. As a result, it becomes possible to perform the discharges of liquid stable at high speeds following the development of bubble in each of the bubble generation areas. Further, it becomes possible to attain the reduction of the number of satellite dots and the vibrations of meniscus. Also, with each of the movable members arranged to face the bubble generation area on the upstream side having its free end on the downstream side, the response of the movable member is in good condition, while the movable members can be arranged one to one for the liquid flow paths, respectively. As a result, the space needed for supporting the movable member is minimized to make the liquid discharge head smaller accordingly.
In accordnace with the liquid discharge method of the present invention, it becomes possible to discharge larger liquid droplets, by use of the liquid dishcarge head of the present invention described above, by discharging liquid at stable discharge speeds with each of bubbles created in each of the bubble generation areas where it is created in the bubble generation area on the upstream side after each of them is created in the bubble generation area on the downstream side among each of the bubble generation areas. With this arrangement, it is possible to stabilize the formation of liquid dorplets of different discharge amounts per nozzle.
Other objectives and advantages besides those discussed above will be apparent to those skilled in the art from the description of a preferred embodiment of the invention which follows. In the description, reference is made to accompanying drawings, which form a part hereof, and which illustrate an example of the invention. Such example, however, is not exhaustive of the various embodiments of the invention, and therefore reference is made to the claims which follow the description for determining the scope of the invention.
In this respect, the term xe2x80x9cupstreamxe2x80x9d and the term xe2x80x9cdownstreamxe2x80x9d used in the description of the present invention relates to the direction of the liquid flow toward the discharge ports from the supply source of the liquid by way of each of the bubble generation areas (or each of the movable members) or represented as expressions related to the structural directions.
Also, the terms xe2x80x9cdownstream sidexe2x80x9d related to the bubble itself means the downstream side in the flow direction described above or in the structural directions described above, or it means the bubble created in the area on the downstream side of the area center of each heating member. Likewise, the term xe2x80x9cupstream sidexe2x80x9d related to the bubble itself means the upstream side in the flow direction described above or in the structural directions described above, or it means the bubble created in the area on the upstream side of the area center of each heating member.
Also, the expression xe2x80x9cessentially in contactxe2x80x9d between each of the movable members and the regulating members used for the present invention may be the approaching state where liquid of approximately several xcexcm exists between each of them or the state where each of the movable members and the regulating members are directly in contact.